Advance database system (part 2)

Advance Database Systems
Overview of RDBMS

Contents
• Introduction to File Processing Systems
• Advantages of Database Approach
• (Database) System Development Life Cycle (SDLC)

Introduction to File Processing Systems
File Processing System :

Advantages of Database Approach
Database System Environment:
• It will be helpful to reiterate our database definition here, that is:
“Database is a shared collection of logically related data, designed to
meet the information needs of multiple users in an organization”

• The figure shows different subsystem or applications in an
educational institution, like library system, examination system, and
registration system. There are separate, different application
programs for every application or subsystem.
• However, the data for all applications is stored at the same place in
the database and all application programs, relevant data and users
are being managed by the DBMS.

1-DataSharing
• The data for different applications or subsystems is placed at the
same place. This introduces the major benefit of data sharing. That is,
data that is common among different applications need not to be
stored repeatedly, as was the case in the file processing environment.
• For example, all three systems of an educational institution shown in
figure need to store the data about students.
• Now the data like registration number, name, address, father name
that is common among different applications is being stored
repeatedly in the file processing system environment, where as it is
being stored just once in database system environment and is being
shared by all applications.

2-DataIndependence
• Data and programs are independent of each other, so change is one
has no or minimum effect on other.
3-ControlledRedundancy
• Means that we do not need to duplicate data unnecessarily; we do
duplicate data in the databases, however, this duplication is
deliberate and controlled.
4-DataIntegrity
• Very important feature; means the validity of the data being entered
in the database. Since the data is being placed at a central place and
being managed by the DBMS, so it provides a very helpful to check or
ensure that the data being entered into the database is actually valid.
• We can also define it as: “Level of Correctness of Data”.

5-BetterDataSecurity
• All application programs access data through DBMS, So DBMS can
very efficiently check that which user is performing which action and
accessing which part of data.
• So, A DBMS most effectively control and maintain security of Data
stored in a database.
6-Faster Development of new Applications
• The database environmental low faster application development
because of its many reasons.
• As we know that database is designed focusing the conclude result to
meet the expectations of the client.

7-Better Concurrency Control
• Concurrency means the access of data base form as number of points
simultaneously.
• Concurrency Control means to access the database in such a way that
all the data accesses are completed correctly and transparently.
• One example of controlled concurrency is the use of ATM Machine for
withdrawal of money(cash).
• All ATM machines of a bank are interconnected to a central database
system worldwide, so that a user can access its account from
anywhere in the world and can get cash from any ATM terminal.
• All this process is managed concurrently using the database systems
and is done in such an efficient manner that no two user face any
delay in the processing of their requests.

8-Better Backup and Recovery Facility
• Sometime happens that a database which was in use and very
important transactions were made after the last backup was made, all
of a sudden due to any disastrous situation the database crashes
(improper shutdown, invalid disk access etc.).
• Now, In such a situation the database management system should be
able to recover the database to a consistent state so that the
transactions made after the last backup are not lost.

System Development Life Cycle (SDLC)

Advance database system (part 2)

Database Development Process (DDP)
• Database Application development Process includes the Following
Stages or steps:
1 Preliminary Study
2 Requirement Analysis
3 Database Design
4 Physical Design
5 Implementation
6 Maintenance

1-Preliminary Study
• First Phase of the database development process is the Preliminary
Study, which is based on the proper study of the system.
• It means that all the parts of the systems, or the section of the
subject organization for which we intend to develop the system must
be studied.
• We should find the relation or interaction of different section of the
organization with each other and should understand the way
information flows between different sections of the organization.
• Moreover it should also be made clear that what processing is
performed at each stage of the system.

2-Requirement Analysis
• Once we have investigated the organization for its different sections
and the way data flows between those sections; Detailed study of the
system is started to find out the requirements of each section.
• In second phase, The detailed study of the system and its
functionality decisions made at this stage decide the overall activity of
the organization.
• Requirements of one section of the organization are fulfilled in such a
way that all the sections in the organization are supporting each
other.
• For example we can say that the results produced by the processing
taking place at one section are used as input for another section.

3-Database Design
• Third phase in the database development process is the database
design.
• This is a technical phase of the process and need handsome skill as a
Database Administrator. This is the phase where the conceptual
design of the database is created. It also known as Conceptual Data
Modeling.
• Entities are identified and given attributes, relationships are built and
different types of relationship are performed by assigning
cardinalities.

4-Physical Design
• In fourth phase, The choice of the DBMS is made on the basis of
requirements and the environment in which the system will operate.
• Implementing a database on a specific DBMS is very important
because it involves the major financial investment of the organization,
and cannot be reverted in case a selected DBMS is not capable of
providing the desired efficiency.
• Also, Assigning meaningful Data Types, Constraints/Limitations and
De-Normalization of Data where required by the real time
scenario/system are to be finalized and processed in this phase.

5-Implementation
• This phase is specific to writing the application programs needed to
carry out different activities according to user requirements.
• We must write application programs in this phase by using
MySQL(my- structured query language) by using DBMS engine known
as XAMPP(Cross platform apache My Sequel PHP Perl).
• We can do coding without any logical error; If we have implemented
all previous phases of database development process correctly.

6-Maintenance
• Maintenance means to fine tune the system and check that the designed
applications systems are fulfilling the purpose for which they are meant.
• Also, this phase may involve designing any new application for the
enhancement of the system.
• Or an already working application may need to be updated or modified to
remove any errors or to add some functionality in the system.
• All these stages are necessary and must be given the necessary attention at
each level to get properly working and good system design and a better
working environment.

Advance database system (part 2)

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Advance database system (part 2)